The present invention relates to a method and apparatus for separably connecting discrete crankshafts in internal combustion engines. More particularly, the invention relates to improvements in a method and apparatus for separably connecting discrete crankshafts in internal combustion engines of the type wherein each of several individual crankshafts can be rotated by a separate cylinder or group of cylinders.
It is already known to reduce the number of cylinders which are in actual use when an internal combustion engine (e.g., the engine of an automotive vehicle) is operated at less than maximum load. Such mode of operation entails considerable savings in fuel and reduces the rate of emission of deleterious combustion products into the surrounding atmosphere. The engine consists of several sections or units each of which comprises a crankshaft, a camshaft and one or more cylinders which can be put to use in order to rotate the respective crankshaft which, in turn rotates the associated camshaft. The crankshaft of one of the units or sections is rotated whenever the engine is running, and one or more additional sections are rendered operative when the operator of the vehicle decides to drive the engine at higher-than-minimum load. For example, a single group of cylinders will be set in operation immediately after starting as well as whenever the engine is to be operated at partial load.
German Offenlegungsschrift No. 28 28 298 discloses a method of operating an internal combustion engine wherein the engine is assembled of several sections or units each of which has an independent crankshaft adapted to be rotated by a discrete group of cylinders. The sections or units of the engine have a common cylinder block. When the operator decides to reduce the fuel consumption, one or more crankshafts are disconnected from a first crankshaft which rotates as long as and whenever the engine is running, and the cylinders which are associated with the disconnected crankshaft or crankshafts are brought to a standstill. In order to reconnect one or more crankshafts to the running crankshaft, it is necessary to accelerate the previously idle crankshaft or crankshafts to the speed of the running crankshaft and to ensure that the freshly accelerated crankshaft or crankshafts assume predetermined angular positions with reference to the running crankshaft. This is necessary in order to achieve satisfactory firing sequence of the cylinders.